A scattershot darkness covered the flanks of the mountain as a host of shapes flashed across the sky. All across the mountains, puffs of snow and rock were thrown skyward by the tremendous impacts of falling objects. The herds scattered as more and more objects dropped from the sky, churning the surface of the mountains with their numbers.

  The clouds above flashed with purple lightning as spores burst within them, dispersing a multitude of contaminants and viruses that instantly began working to alter the climatological balance of the planet’s atmosphere. Heat built up rapidly, increasing the air pressure and causing actinic bolts of lightning to arc from cloud to cloud, dispersing them as a viscous, toxic rain.

  In minutes, the newly risen sun was obscured by the sheer mass of spores falling from the heavens. Terrified yrenbacks ran backwards and forwards across the mountain sides, leaping through the deep snow in their blind panic. Churning motion erupted from the steaming spores that had landed in their midst, flashing claws and alien screeches as the creatures within them emerged and sought something to kill. Driven into a frenzied killing fury by the hive mind and bio-engineered, super-adrenal chemicals, the first wave of tyranid invaders hacked entire herds of the grazing animals to bloody ruin before collapsing and dying, spent by the fury of their assault and their inability to survive the freezing temperatures.

  Thousands of tyranid organisms in the first wave perished as the numbing cold of Tarsis Ultra froze them within minutes of their arrival. After burning virtually all their bodily energies in their initial surge of violence, and without reserves of fat, none could survive more than a few minutes before perishing.

  But none of this mattered, for as each creature died and the hive mind became aware of the local conditions on the prey planet, it simply adjusted the biological physiology of its warrior organisms, enabling them to produce more insulating tissue and energy reserves that would allow them to survive for longer periods.

  AMID THE LOAMY earth of the lower forests, the thick, biological rain soaked into the tree canopy and saturated the earth with its bacteria-laden substance. Microbes containing the genetic blueprint of tyranid fauna spread rapidly through the ground, assessing and digesting the chemical content of the soil before turning that energy into horrifyingly fast growth spurts.

  Multicoloured fronds ripped their way through the silver bark of the trees and twisting vines and creepers surged from

  the moistened ground. Again, the cold of Tarsis Ultra dramatically shortened the plants’ lifespan, but as each leaf and creeper died, it vomited a host of fresh spores into the atmosphere and the cycle began again.

  As each generation of plant went through its brief life cycle, the chemical reactions fermenting in the ground began raising the temperature of the surrounding air. Streamers of heated air drifted from the ground, warming the burgeoning plant life until the rate of growth was rising exponentially. Jagged spore chimneys of thick, vegetable matter broke through the hot earth and pushed skyward, their root structure burrowing through the permafrost to the nutrient-rich soil below. Hot steam and exhaust gasses from the biological conflagration below belched from the chimneys, sending yet more spores high into the atmosphere to be spread by the prevailing winds. As the atmosphere heated even more, strong updrafts of warm air rose, meeting the cold air descending from the mountaintops to create freak weather patterns that spread the contamination of the tyranid organisms even further.

  The invasion of Tarsis Ultra had begun.

  DESPITE THE INABILITY of the Imperial fleet to hold back the tyranid invaders, Tarsis Ultra was not without defences of her own. Ground-based batteries of defence lasers fired skyward and hundreds of orbital torpedoes roared into the upper atmosphere on blazing tail plumes.

  The defence lasers slashed through the sky, but the rapidly mutating content of the air had one more adaptive surprise for the defenders of Tarsis Ultra.

  One of the greatest problems for ground-based laser weapons was the reduction in power they suffered over long distances, called ‘thermal blooming’. As a laser beam travels through the air, small quantities of its energy are lost to the surrounding atmosphere as heat, which causes disturbances in the air and disrupts the optical path of the beam. Not only does this impair accuracy, but it spreads the beam wider, thus weakening the energy delivered to its target. For the colossal energies produced by the defence lasers, this was not normally a problem, but each beam was passing through dozens of rapidly fluctuating temperature patches in the air, causing them to impact with greatly reduced power.

  Many of the smaller organisms suffered at the hands of the defence lasers, but the majority of the tyranid creatures had little to fear from them.

  But torpedoes have no such barriers to performance and these weapons reaped a fearful tally amongst the gathering predators. Hundreds of torpedoes exploded amongst the bloated spore ships of the tyranid fleet, destroying some and fatally wounding others. Scores of alien creatures perished and fell through the atmosphere as bright, fleshy meteors, haemorrhaging their lifeblood like comets’ tails.

  The skies above Tarsis Ultra were what Imperial strategos referred to as ‘target-heavy’ and every torpedo found its mark in a tyranid creature. Within two hours, over five hundred confirmed kills had been reported by the silo commanders, along with desperate requests for additional ordnance to fire. Faced with so many targets, each silo exhausted its supply of weapons after another hour of firing.

  Against any conventional invaders, the defences of Tarsis Ultra would have caused utter devastation and crippled any attempt to invade.

  But the tyranids were far from conventional invaders.

  FROM THE AIR, the hydro-skiff resembled a speeding silver bullet as it roared along the frozen surface of the hydroway. Its passenger compartments were laden with soldiers of the Logres regiment making their way back to Erebus, its speed approaching two hundred kilometres per hour as its giant, prop-driven engines hurled it along the frozen canal surface.

  A mist of ice crystals billowed in its wake as the hydro-skis angled to take the skiff around a bend in the canal, rounding a series of low hills capped with a thatch of evergreen firs. Sparks flew as the offside ski grazed the mag-rails on the side of the canal, the pilot having taken the turn a little too fast for comfort. But concerns of safety were now outweighed by the need for speed. They had seen the heavens criss-crossed by bright streaks of lasfire, and the pale blue of the sky to the west was laced with cloudy pillars from firing torpedo silos. No one needed to tell the men of the Logres regiment what was happening, and that it was time to head for the safety of Erebus.

  Unnatural twilight was falling as tyranid spores filled the sky above, long shadows cast by chittering black clouds that spun and swooped like flying oil slicks. Soldiers peered nervously through the steamed windows at the gathering darkness, willing the skiffs pilot to coax his machine to yet faster speeds.

  A pair of the black clouds dropped through the air, looping downwards to fly parallel to the skiff, a third descending in a lazy spiral ahead of it. Officers watching through the roof periscopes shouted at their men to stand to, chivvying them to the windows and bellowing orders to fire at will.

  Blasts of freezing air filled the skiff as windows were forced open and barrels of lasguns pushed through. Lasbolts snapped upwards, punching into the black flocks that pursued the skiff. Occasionally, a twisted shape would tumble to the snow, but such precious victories were few, and despite the terrific speed of the skiff, the flocks drew nearer still.

  Cries of fear echoed along the length of the passenger compartments as the flocks began to overtake the skiff and the soldiers had their first glimpse of the enemy. Grotesque, membrane-winged creatures with leering, fang-filled maws and clawed limbs surrounded them. Lasbolts tore amongst the aliens, but for every one that was downed, a “hundred more remained. They swooped over and around the skiff, spitting black gouts from weapon orifices that peppered its metal skin like handfuls of thrown stones. Glass smashed and men sc
reamed as the aliens’ fire struck them, their armour cracking and dissolving under the impacts.

  Medics ran to the wounded, peeling off bloody flak vests and applying pressure to the ragged holes in the soldiers’ bodies, then recoiled in horror as they saw clutches of writhing, beetle-like creatures boring deep into the men’s flesh.

  Scrabbling claws tore at the skiffs roof, gouging long tears in the thin metal. The skiff swayed from side to side, throwing more sparks as the pilot fought to compensate for the additional weight and drag of the attackers. Soldiers fired through the roof, killing the flying beasts in their dozens, but unable to dislodge them all.

  Muscular taloned arms reached in and dragged a screaming soldier through a hole in the roof, his cries cut off as the rushing wind snatched away his breath. His comrades fought to pull him back, but another volley of the flesh-eating creatures slew the would-be rescuers in a hail of fire.

  The skiff screamed around another bend in the icy canal, only to be faced by yet another flock of the winged monsters, swirling in an impenetrable cloud and blocking the skiffs path with their bodies. The pilot reacted instinctively, slamming on the air brakes and wrenching the controls to one side. Barbed brakes deployed from the skis, throwing the skiff into an uncontrollable skid.

  The rear end of the skiff fishtailed, the passenger compartment slewing around until it was travelling sideways. Wider than the canal, its back end caught the edge of the mag-rails and flipped it over onto its side. At such high speeds, the impact ripped the passenger compartment open and tore the coupling to the engine with it, sending it spinning into the air to crash down onto the ice a hundred metres further down the canal where it exploded in a searing orange fireball.

  Flames billowed skywards as the wreckage skidded along the canal for another six hundred metres, the heat from the flames melting the ice as it slid. Amid the carnage of the crash, a few pitiful survivors crawled from the wreckage, battered, bloodied and dazed.

  Even before they had a chance to freeze to death, the winged gargoyles were upon them, biting and clawing at their helpless prey until there was no one left alive.

  The first victims of the land war of Tarsis Ultra had been claimed.

  FROM THEIR PERCH high on the roof of their warehouse hideout, Snowdog and Silver watched the distant contrails of torpedoes as they climbed through the purple skies into the upper atmosphere.

  The devotional holos, normally full of nameless preachers demanding prayers to the Emperor, had been displaying a non-stop procession of warnings against the dangers of contact with xeno species, Snowdog didn’t know what was happening with the war, but was pretty certain that there must have been a screw-up somewhere along the line, because you didn’t start firing ground based weapons except to prevent an imminent invasion.

  ‘This does not look good,’ said Snowdog.

  ‘Nope,’ agreed Silver, ‘It sure doesn’t.’

  LORD INQUISITOR KRYPTMAN stood in an armoured viewing bay atop the Governor’s Palace, watching the same scenes with a similar feeling. With the news that the fleet had been forced to disengage, his hopes that this invasion could be stalled before it reached the surface of the planet had been shattered. He cast his gaze across the landscape one last time, knowing that even were they able to defeat the aliens, this world would never be the same again.

  Orders had been issued to all officers on tactical doctrine and the proper conduct to be followed during conflict with the tyranids. Experience bought with uncounted lives was even now circulating amongst the soldiers of Tarsis Ultra and Kryptman hoped that the sacrifice of those who had died to gather that information would not have been in vain.

  As he watched the beginning of the tyranid invasion, Magos Locard joined him in the bay, hands clasped before him and mechadendrites swaying gently above his head.

  ‘So it begins again,’ mused the inquisitor, watching the swirling, multi-coloured sky.

  ‘Indeed,’ said Locard. ‘Were it not such a monstrous thing, it might be considered aesthetically pleasing. It is nature driven into paroxysms of creation.’

  ‘Creation, yes, but there is nothing natural about this. It is creation designed to destroy and consume.’

  ‘An interesting dichotomy, yes?’ observed Locard.

  ‘Yes, but one for another time perhaps. How goes your research?’

  ‘It progresses. The facilities here are lacking in some regards, but they are sufficient for my needs. The samples taken from the xeno creatures recovered from the Vae Victus have helped immensely, but their genetic structure shows evidence of mutation. Evidently, the tyranids have entered another iteration of evolution since the consumption of Barbarus Prime.’

  Kryptman turned to face the magos and nodded. ‘I had suspected as much.’

  To achieve our goal, it seems clear we will need to somehow obtain a gene sample that is as close to the hive’s original

  structure as possible, one that has not been subjected to mutation at the behest of the overmind.’

  ‘And how do you intend to obtain such a specimen?’

  ‘Ah, well that I do not yet know,’ admitted Locard.

  ‘Find a way,’ ordered Kryptman.

  URIEL WATCHED LEARCHUS and Pasanius march along the front lines of the city’s defences and fought the urge to join them. Little time had passed since he had been a veteran sergeant himself, and the old desire to check on the men under his command still came to the fore on the eve of battle. He had greater concerns now, he reminded himself, as he checked the data-slate to ensure that everything in his sector of responsibility was as it should be.

  From above, the plain before the city walls resembled the top of a racetrack with curved trenches linking the two sides of the valley. Three entrenchments crossed it, progressively narrowing as they neared the city walls, but Uriel knew that these were nothing more than temporary defences. The first wave of tyranids would come at them from the air, pinning them down while the bulk of the tyranid army approached on foot. Sebastien Montante had assured him that the valley sides were well defended with enough guns to make any aerial attack unfeasible. Uriel had his doubts, knowing that the sheer scale of a tyranid invasion was beyond the comprehension of most people who had never seen one.

  Seven thousand men occupied the first trench, six thousand the second and another two thousand the third. The remainder of the soldiers waited within the walls of Erebus itself, held in reserve until needed. Rumbling before the wall, its armoured flanks bristling with guns and its crenellated battlements swarming with soldiers, was the Capitol Imperialis of Colonel Octavius Rabelaq. Emblazoned with the heraldry of the Logres regiment, the massive rhomboid-shaped command vehicle rose nearly fifty metres from the ground. From here, Rabelaq could direct his soldiers and maintain command and control over the battle. Its tracks were wider than a road and four Leman Russ battle tanks could fit within the barrel of its main gun. It was a fearsome reminder of Imperial power and its might was plain for all to see. Smaller tanks surrounded the Capitol Imperialis, like ants around an elephant, passing through the gates in the wall towards the front line.

  Those tanks that had already taken position idled in well-sited berms, with flared aprons of flattened snow behind them to allow them to reverse out and withdraw to the next line.

  Soldiers in dirty overwhites huddled in their dugouts, clustered around plasma-wave generators, cooking their rations. The men clearly relished what might be their last hot meal for some time, and Uriel knew that little improved morale more than hot food and beverages. Here, Montante had excelled himself, handling the logistical nightmare of feeding and equipping tens of thousands of soldiers with the skill of a veteran quartermaster. He had organised vast kitchens to supply the soldiers defending his city with regular hot food and ensured that the commanders had a reliable supply train.

  Everything had been organised with admirable efficiency and he could see the teachings of the Codex Astartes in the precise layout of the defences. Uriel was reminded of the
schematics he had seen depicting the defences of the northern polar defence fortress on Macragge during the First Tyrannic War, though he hoped to avoid the outcome of that battle.

  Satisfied that all was as it should be, he marched along the slush-covered duckboards of the trenches towards the front line. A thick, two-metre berm of snow had been built before the trench to absorb any incoming fire, since, rather than exploding away from projectiles like sand, snow would anneal under the impact and become a stronger, more effective barrier.

  Buckets of water had been repeatedly poured down the slope of the snow barrier before the lip of the trench, making a glass-smooth surface that would hopefully prove extremely difficult for the aliens to scale.

  ‘Any word on when we can expect to see them?’ asked Pasanius, joining Uriel on the trench’s firing step.

  ‘Soon,’ answered Uriel as Learchus marched over.

  ‘You have done fine work, Learchus,’ said Uriel, gripping his sergeant’s hand in welcome.

  Learchus nodded. ‘The soldiers here are good men, brother-captain, they just needed reminding of the teachings of the Codex Astartes.’

  ‘I’m sure you gave them a very pointed reminder,’ noted Uriel.

  ‘Where necessary,’ admitted Learchus. ‘I was no harsher than any other Agiselus drill sergeant.’

  Both Pasanius and Uriel winced as they remembered the severity of their training on Macragge. Neither had any doubt that Learchus had put the soldiers here through hell in order to prepare them for the coming war. But if it made them better soldiers, then it was a price they should be thankful for.

  ‘Where are the Mortifactors and the Deathwatch to be stationed?’ asked Learchus.

  Uriel pointed towards the southern reaches of the trenches, his brow furrowing at the memory of the confrontation with Astador and Kryptman in the orbiting space station. He had lost control and the shame of that lapse still burned inside him. He was a Space Marine in the service of the Emperor and was above such petty considerations as temper. But the death of so many innocents on Chordelis and the stain left within his soul by the Bringer of Darkness had overcome his normally unbreakable code of honour.